Calculate a daily value of reference evapotranspiration, useful for vegetation (incl. crop) models. The module code is based on FAO-56 Penman-Monteith method. The implementation is based on several sources (see moduleReferences), but particularly useful was the Evapotranspiration R package (Guo e...
Calculate a daily value of reference evapotranspiration, useful for vegetation (incl. crop) models. The module code is based on FAO-56 Penman-Monteith method. The implementation is based on several sources (see moduleReferences), but particularly useful was the Evapotranspiration R package (Guo et al. 2016, 2022 (v1.16), https://cran.r-project.org/web/packages/Evapotranspiration/index.html). Note: values of C_n
and C_d
are fixed for using the grass cover reference (900 and 0.34); values for the alfalfa reference are 1600 and 0.38.
Name | Type | Description |
---|---|---|
par_elevation | float | elevation above sea level of the soil where the reference evapotranspiration is to be calculated. |
par_temperature_daily_mean | float | Mean daily air temperature above the ground surface where the reference evapotranspiration is to be calculated. |
par_temperature_daily_min, par_temperature_daily_max | float | Minimum and maximum daily air temperature above the ground surface where the reference evapotranspiration is to be calculated. |
par_netSolarRadiation | float | Solar radiation energy received by the soil surface, discounting loss by albedo reflection. |
windSpeed | float | Wind speed at 2m above the soil surface (fixed to 2 as constant in code, as per Allen et al. 1998 recommendation in absence of data). |
Name | Type | Description |
---|---|---|
ETr | float | The evapotranspiration in millimeters of water per day assuming a reference surface that is not short of water and covered by a hypothetical grass (or alfalfa) reference crop with specific characteristics. It is referenced in the bibliography also as ETo. |